Snowpack is omitting an import from the very top of the file

[noseratio]

My index.js file looks like this:

// remove this line and @esfx/cancelable will disappear from web_modules
import { CancelError } from "@esfx/cancelable";
import { CancelToken } from "@esfx/async-canceltoken";

If I remove the top comment line and invoke npx snowpack build, @esfx/cancelable will disappear from web_modules.

This is happening with Snowpack v2.18.5 and 3.0.0-rc.2.

I'll update this issue with a link to a repro-repo in a few mins. Edited, repo: https://github.com/noseratio/snowpack-import-bug

[FredKSchott]

Thanks! That's really strange... we should just be passing the file to es-module-lexer. Will need to add some logging to the scan-imports.ts file to debug

[user72356]

UPDATE: still happening on 3.8.8

I have the exact same issue.

This is with Snowpack 2.18.5

I found that in my index.js (main entry file), my first import was being ignored by Snowpack. If I only have 1 import, then the web_modules folder doesn't get generated, and if I have more than 1 import, the first import is discarded entirely.

This doesn't work:

import _ from 'lodash';

export function sayHi()
{
    alert(_.version());
}

This works:

// comment line here
import _ from 'lodash';

export function sayHi()
{
    alert(_.version());
}

[noseratio]

Tks. I'll verify under Ubuntu, then will create an issue for keeping track of it.

[user72356]

Cool. I literally spent hours today trying to understand what was happening (first time user of Snowpack, I thought the problem was with me!)

[FredKSchott]

ugh sorry this is happening! I can confirm that this is not happening on Linux (just ran in a container: https://fredkschott-snowpack-import-bug-8qqr.github.dev/). so it must be windows only. Would love your help to debug:

• can you confirm which version introduced this? Still seeing this on 2.18.4? 2.18.3?
• any logging that you can add to scan-imports.ts would be great! Specifically interested in the state of contents as it moves through the parseJsForInstallTargets() function.

[noseratio]

I think I've figured it out. Not just on Windows, I did repro it on Debian as well, by cloning my repro.

The issue is caused by the UTF-8 BOM suffix at the beginning of ./public/index.js file:

The problem is gone as soon as I remove these three BOM bytes from the beginning of the file.

@FredKSchott,

can you confirm which version introduced this? Still seeing this on 2.18.4? 2.18.3?

I haven't yet, I suspect it it's been always there but is specific to the files with UTF-8 BOM suffix 🙂

Would you still be interested in the log files? Should we convert it to an issue?

@user72356, could you confirm it's the same problem for you?

Thanks.

[FredKSchott]

oh wow! that's fascinating. Thanks for digging.

I'm curious where the line is getting stripped, it may actually be esbuild. Will need to dig further with console logs to see at which point the contents no longer contains the line

[kwaclaw]

Same issue with 3.3.5 I am on Windows, does not affect all files, but most.
Maybe an issue with a UTF-8 BOM in some files but not others?